The story of a factory-experimental, one-of-one, fuel-injected, independent-rear-suspended, 428CJ-powered 1968 Shelby Mustang coupe

Feature Article from Hemmings Muscle Machines

Modern performance cars are advanced machines. Fuel injection precisely meters the engine's gas intake, resulting in greater efficiency, better gas mileage and cleaner emissions. Independent rear suspension helps calm down the ride on the straight and narrow and can aid in ride control when the road gets twisty or bumpy or both. Four-wheel disc brakes make stopping all that weight as effortless as big-cube torque accelerates it.
Had you not already seen the pictures, and you knew that we were talking about a 1960s-era car, you might have guessed a mid-year Corvette, or maybe some wild European exotic, would fit the criteria. Had we said that we were talking about a Mustang, perhaps you would have flashed to the 1999-2004 SVT Cobra, with its massive power and independent rear suspension. But a Mustang nigh on four decades old that embodies these qualities? Surely such an animal never roamed the streets of our fair nation?
There was one. The stripe on the front quarter calls it EXP500, but it's known by another name: The Green Hornet.
To explain the genesis of the Green Hornet, we need to go back and discuss its immediate predecessor, Li'l Red. Red was a '67 Mustang hardtop built to Shelby specs (including all of the visual trimmings) and given a Paxton supercharger to force-feed its 428 cubic inches of thunder. Visual tweaks, beyond the usual Shelby touches, included a black vinyl top, ten-spoke Shelby wheels, and a new ducktail trunk lid and endcaps. It had a nasty habit of blowing out tailshafts, such was the power. Fred Goodell, Shelby's chief engineer at the time, built it for himself, combining showcar looks with experimental skunkworks-type power. He never got to drive it much--apparently Bill Cosby took a fancy to it and, as a pal of Carroll Shelby's, spent quite a bit of time in it. It was also part of Ford's performance display at a dealer event in August of 1967; Los Angeles District Sales Manager Lee Grey took a shine to it, thinking that it could help reinvigorate a slowing Mustang market. Grey borrowed it for a week to conduct some, ahem, market research--and response was so strong that he convinced Lee Iacocca to create the GT/California Special. Around the same time, Li'l Red spent time in Dearborn as Ford considered a national version of the GT/CS, tentatively called GT/CC, or GT/Sports Coupe.
All of this led to an issue: Carroll Shelby had an independent rear and a fuel-injection unit to test, and no testbed to put it on. So, Ford sent over an early production Lime Gold '68 hardtop with matching Deluxe interior (complete with consoles and wood trim), sporting a 390/C6 combo, shipping it from Dearborn to Shelby's facility up the freeway in Ionia, Michigan. Changes commenced almost immediately.
The 390 was summarily yanked and replaced with an experimental 428CJ (with all factory smog equipment intact) fed via an experimental Conelec electronic fuel-injection unit, developed by former Bendix engineer Dave Long, who spearheaded work on Bendix's stillborn Electrojector project. (Once Bendix turned its attention elsewhere, Long split for Conelec.) Though also in pilot production for marine use, Ford was said to be eyeing up the Conelec system for full-sized Fords and Mercurys in light of the new, more stringent 1970 emissions regulations. Conelec kept fuel pressure below 15 p.s.i., which favored longer and more frequent injection pulses over timed injection. This also allowed better vaporization, which was seen as an essential component of reducing emissions. Motor Trend tested a prototype Mustang--one of ten said to be fitted with the Conelec system--and discovered that, when programmed for power rather than emissions, fuel economy improved. (Conelec fuel pumps were later used in Ford's successful SCCA Trans-Am efforts.)
The other experimental bit of engineering wasn't visible without taking the rear wheels off. The independent rear suspension cradle bolted directly into the rear leaf spring perches, but still used a Ford 9-inch center section. Coil springs, rear anti-roll bar, and lateral links (appearing not unlike the "quad shocks" that many Fox-body Mustangs came with in the 1980s) are all part and parcel of the program. Rear disc brakes were in the equation as well.
The factory C6 was also pulled, and an F350 truck-spec C6 was installed instead--with a Lincoln torque converter and a cast-iron truck tailshaft. The front suspension was Shelby-ized as well, and a stock set of ten-spoke wheels and F60-15 tires were included. The body and interior were given the Shelby treatment. A complete '68 nose with functional ram air hood, and a tail panel that accommodated the '65 Thunderbird taillights were installed, and the GT/CS side scoops remained. Famed pigment squirter Sonny Fee put on a show-car quality paint job: Three coats of Gold Luster Green lacquer with gold metallic mica over the original topcoat, hand-rubbed between coats, and then two clear coats of lacquer on top of that. Shelby ornamentation and the white-and-gold EXP500 stripes were also added at that point. It quickly earned the nickname "Green Hornet"--ostensibly because of Shelby's friendship with Li'l Red-hogger Bill Cosby, whose cast of characters acknowledged the Green Hornet as their favorite super hero.
Performance was monstrous: 0-60 times in the 5.7 second range and top speeds of 157 mph were clocked at Ford's Romeo proving grounds. Considering the 3.0:1 ratio in that 9-inch rear, a 3,500-pound test weight, and the tire technology available at that time, these are astounding numbers. By way of comparison, Car and Driver tested a GT500 when it came out, and got a 6.5-second 0-60 mph time, a 15.0-second, 95-mph quarter-mile, and an estimated 128 mph top speed. Then again, their test weight was in the 3,800-pound range.
But like all experiments, this one had to come to an end. For reasons lost in the mist of time (though most likely due to cost issues), neither the Conelec fuel injection nor the independent rear made series production. It was widely assumed that the Green Hornet had been crushed, since no one knew of its whereabouts.
Turns out, it was around all along--rather than being scrapped, it was sent to Ford's Employee and Auction Resale Lot in Dearborn. By the time it was in the yard, it was just an old Mustang: The special independent rear had been stolen and replaced with a bog-standard Fairlane axle, and the Conelec EFI had similarly been swiped and replaced with a police interceptor intake and four-barrel carb. The yard supervisor, Robert Zdanowski, bought it for $3,000 as a family car--he knew that it was the only Shelby notchback of its kind--but he sold it six months later when, as he wrote in a letter, "the Green Hornet proved to have too much power to be a 'safe' family car. (On rainy days, the rear end would slide off the asphalt roads near our home.)"
Zdanowski sold it to Don Darrow, owner of the Ford dealer franchise in Cheboygan, Michigan. Darrow promptly added a white vinyl top, 14-inch styled steel wheels with GT caps, and white-stripe Michelins. It only accumulated 30,000 or so miles during the Darrows' ownership, mostly owing to its spendthrift gasoline-drinking habits. Don's son, Randy, recognized it from Paul M. Newitt's book, GT/California Special Recognition Guide and Owners Manual, and contacted the author. Until the book emerged in the late '80s, neither Darrow had any idea of the special machine they had in their possession for those two decades. The Darrows squared their car with Fred Goodell, who built it in the first place and who was tickled that it still existed. Other evidence, besides the car's original 428 and beefed-up C6 still in place, included the holes drilled in the firewall and trunk floor to pass wiring and mount the fuel pump, respectively, to help feed the Conelec injection.
Five years of on-again, off-again restoration attempts ended when Martin Euler of Classic & Muscle Mustang Restorations in Midland, Michigan took over. In less than two years, Euler took the Green Hornet down to bare metal (discovering the original coat of Lime Gold Metallic paint beneath the custom coats of dark green metallic lacquer) and, thanks to some guidance from Goodell, built it as close to what God and Carroll Shelby intended as anyone could muster.
For his part, Goodell contributed (among other components) an air-valve body for the missing Conelec EFI system. Indeed, today the system doesn't even reside on the car: it stays in a box in the garage. (Better displayed that way, no?) The intake runners and injectors were hand-fabbed, and the throttle body is a cast unit. In keeping with the fuel-injected tradition, a Holley ProJection unit lived under the air cleaner at the time of restoration.
The other amazing restoration item is the rear suspension. It's fair to say that it wasn't rebuilt: rather it was simply built, cut from whole cloth. Euler engineered, with guidance from Goodell but utilizing no existing photographs or plans, a complete bolt-in IRS system. There's nothing slapdash or hand-built looking in here: other than the yellow springs and the recent Konis, you'd think that this was something that rolled off the assembly line. Euler attempted to market this bolt-in independent rear, but with little success.
The Green Hornet is now part of Craig Jackson's select collection of ultra-rare muscle cars--a lone Ford in the Barrett-Jackson Auction magnate's private garage full of ultra rare one-of-one high-optioned GM and Mopar muscle.
When we photographed the Green Hornet, it could not be coaxed into running; the Conelec remained off the car, and we didn't even have a peek under the air cleaner to determine whether ProJection or a more common carburetor was living atop the intake manifold. (The notion that we arrived to photograph it just four days after one of Craig's record-breaking January weekends in Scottsdale probably didn't push it high on the list of priorities, either.) Thus is the greatest shame of it all: That what could arguably be one of the most drivable and driver-friendly Mustangs ever built couldn't go out for a spin.
Perhaps this is why these components never made it to production: too fragile. Not ready for prime-time. But the Green Hornet remains a beacon, a glimmer of evolution in a time of caveman cubes and cars as blunt instrument. Change would have to come. But not just yet. That would have to wait.
Owner's View
On rainy days, the rear end would slide off the asphalt roads near our home.--Fred Goodell
PROS
+ Documented Shelby prototype
+ Groundbreaking ideas still not used
+ Virtually impossible to even clone one
CONS
- Not actually drivable at press time
- Would you take the chance if it was?
- Virtually impossible to even clone one
Club Scene
Shelby America Automobile Club
P.O. Box 788
Sharon, Connecticut 06069
fax: 860-364-0769www.saac.comsaac@saac.com
Dues: $47.50/year • Membership: 5,500
SpecificationsPrice
Base price: N/A
Options on car profiled: Conelec fuel injection, independent rear suspension
Engine
Type: OHV V-8, iron block and heads
Displacement: 428 cubic inches
Bore x Stroke: 4.13 inches x 3.98 inches
Compression ratio: 10.5:1
Horsepower @ rpm: 355 @ 5,400*
Torque @ rpm: 420-lbs.ft. @ 3,200rpm*
Valvetrain: Pushrod operation, hydraulic valve lifters
Main bearings: 5
Fuel system: Conelec electronic multiport fuel injection, electric fuel pump
Lubrication system: Pressure, gear-type pump
Electrical system: 12-volt
Exhaust system: Dual exhaust
Transmission
Type: Heavy-duty Ford C6 three-speed automatic with Lincoln torque converter
Ratios 1st: 2.46:1
2nd: 1.46:1
3rd: 1.00:1
Differential
Type: Ford 9-inch center section
Ratio: 3.00:1
Steering
Type: Recirculating ball, power assist
Turns, lock-to-lock: 4.0
Turning circle: 37 feet
Brakes
Type: Four-wheel disc, hydraulic activation
Front: 11.3-inch Kelsey Hayes vented discs
Rear: 11.3-inch Kelsey Hayes vented discs
Chassis & Body
Construction: Unit-body construction
Body style: Two-door coupe
Layout: Front engine, rear-wheel drive
Suspension
Front: Independent, upper wishbones, lower control arm with drag strut, 0.94-inch anti-roll bar, coil springs, telescoping shock absorbers
Rear: Fully independent; lower control arms; coil springs; telescoping shock absorbers; lateral links; anti-roll bar
Wheels & Tires
Wheels: Shelby aluminum 10-spoke
Front: 15 x 7 inches
Rear: 15 x 7 inches
Tires: Goodyear Polyglas
Front: F60-15
Rear: F60-15
Weights & Measures
Wheelbase: 108 inches
Overall length: 186.6 inches
Overall width: 70.9 inches
Overall height: 51.6 inches
Front track: 58.0 inches
Rear track: 58.0 inches*
Curb weight: 3,450 pounds**
Capacities
Crankcase: 5 quarts
Cooling system: 23.5 quarts
Fuel tank: 17 gallons
Calculated Data
Bhp per c.i.d.: 0.83*
Weight per bhp: 9.71 pounds*
Weight per c.i.d.: 8.06 pounds*
Production
This Shelby Mustang was a prototype unit for component testing and was not sold through regular dealer channels. It is the only one in existence.
Performance
0-60 mph: 5.7 seconds
0-100 mph: 11.4 seconds
Top speed: 157 mph
* indicates information on (or extrapolated from) a stock 1968 Shelby GT500; prototype data unavailable
** according to previously published sources

This article originally appeared in the September, 2006 issue of Hemmings Muscle Machines.